FR2717769A1 - CV joint. - Google Patents

Abstract

The seal comprises an outer part (1), with outer grooves (3), and an inner part (9), with inner grooves (13) facing each other to receive a torque transmission ball (31). The balls are guided in windows (27) of a cage (24) between the outer (1) and inner (9) parts. The grooves (13, 3) are, starting from one side (11) of the joint, without an undercut, and the cage (24) is guided with a hollow spherical surface (25) on an outer spherical surface (21) of the inner part (9). The grooves (13) of the inner part (9) are restricted to a length (17) consisting of the stroke (18) of the balls (31) for the maximum inclination between the inner (9) and outer (1) parts, and a safety length (19) at both ends, then they turn into an enlarged section (14, 15). The inner part (9) is formed without removing material, and the grooves are stamped to final dimension.

Description

The invention relates to a constant velocity joint, which comprises a part

  external hollow, in the internal surface of which external rolling grooves are arranged in meridian planes with respect to the longitudinal axis of the external part, and which comprises an internal part arranged in the internal space of the external part; in the external surface of this internal part, internal rolling grooves are arranged in meridian planes with respect to the longitudinal axis of the internal part, which are opposite the external rolling grooves, the internal rolling grooves and the external rolling grooves situated respectively opposite opposite jointly receiving a ball for the transmission of the torque. The balls are guided in windows of a cage arranged in an intermediate space between the internal surface of the external part and the external surface of the internal part, and the internal rolling grooves and the external rolling grooves are produced, starting on one side of the joint, without undercut, and the cage is guided with a hollow spherical cap surface on a surface

  outer spherical of the inner part.

  Such a constant velocity joint is described in document DE 37 39 867 C2. When producing the internal parts by forming without removing material, considerable forces are required, since the material has to flow. In particular, the material must be pushed back to the final dimension in the region of the rolling grooves for their forming, which can be done, for the shape illustrated therein, only by applying pressure from the inside. However, this negatively influences the accuracy to be observed. The tools that receive the inner part during forming widen due to the high pressure. In addition, the expenses

  energy for this mode of forming are enormous.

  Consequently, the objective underlying the invention is to produce a constant velocity joint comprising an internal part and / or an external part which can be produced with low forces and thus with little energy, however with high accuracy. without removal of material with regard to functionally important contours. According to the invention, this objective is achieved by the fact that the rolling grooves of the inner part and / or of the outer part are limited to a length which consists of the stroke of the balls in the inner rolling grooves, which results from the maximum inclination provided by the construction between the inner part and the outer part during rotation, and from a safety length at both ends, and by the fact that the rolling grooves are transformed at least a end respectively in a groove section which has an enlarged cross section with respect to the rolling grooves, and by the fact that the inner part or the outer part which has the shortened rolling grooves is made

  by forming without removing material.

  Thanks to the shortening of the rolling grooves, in particular the internal rolling grooves, to a maximum length which corresponds to the stroke of the balls during the inclination of the internal part relative to the external part from one of the extreme positions up to '' at the other extreme position, when the longitudinal axis of the external part and the longitudinal axis of the internal part are in a plane, added with additional security at the ends for reasons of solidity, it results in a considerable reduction of the surfaces to be produced with exact measurement without removal of material. Thanks to this, it is possible to significantly reduce the forces required for forming without removing material. A further reduction in forces results from the fact that the enlarged groove section which connects axially to the rolling grooves can be used for the reception of the discharged material. This also results in improved dimensional stability during forming without removing material, and thus obtaining close tolerances. In this case, forming without removing material can be carried out in several stages, the last stage being a stamping which takes place between two tools and which extends at least over the rolling grooves. Preferably, in addition to the rolling groove, all the functional surfaces are simultaneously stamped to the final dimension, for example also the outer spherical surface of the inner part which serves to guide the cage. In this case, the forming is carried out in the form of a pressing stamping with the advantages which result therefrom with regard to the reduced need for

  strengths and improved accuracy.

  As an example, the solution described in document DE 39 04 655 CI (US-PS 4 968 287) is suitable for producing the cross section

  and the shape of the interior rolling grooves on their active region.

  Dimensional stability can be further improved while simultaneously further reducing the processing forces required by the fact that the inner bearing grooves are provided with at least

  a groove that extends along their length.

  Preferably, the safety length is dimensioned so that the balls can be retained and controlled even more securely in the extreme positions they occupy during tilting.

  maximum of the internal part compared to the external part.

  The characteristics of the invention stand out particularly advantageously in connection with a seal which is produced in the form of a fixed constant velocity joint and in which the external part having the external rolling grooves is closed by a closing element on the side from from which the absence of undercut begins, and the inner part is provided towards the closure element with a guide surface which is produced in the form of a spherical surface, the outer spherical surfaces being further arranged on the side of the inner part that is diverted from the surface

guide.

  When the inner part and the outer part are centered with respect to each other on the one hand by the support of the guide surface of the inner part against a bearing surface of the closure element or against a guide element supported thereon in the direction of the longitudinal axis of the outer part, and on the other hand thanks to the support of the balls in the outer rolling grooves and in the cage, a clearance being provided between the external surface of the cage and the internal surface of the external part, there is for example the possibility of using a separate external part produced in the form of a part molded in sheet metal or

  produced by forming without removing material.

  Another preferred variant of embodiment proposes that the inner part and the outer part be centered with respect to each other on the one hand thanks to the support of the guide surface against the bearing surface of the part of the closing element or against a guide element supported thereon in the direction of the longitudinal axis of the outer part, and on the other hand by guiding the cage comprising a spherical outer surface on a hollow spherical surface of the outer part. The embodiment with direct guidance of the inner part on a surface of the closure element, which corresponds to the guide surface, is apparent for example from document DE 37 39 867 C2 (US-PS 49 50 206), and such embodiment in which a separate guide element is provided, can be seen from document DE 42 08 786 C1 (US-SN03 25 02), as well as from the German patent application

P 43 17 606.2.

  As for the two embodiments, it has been proposed in addition that the closure element can be adjusted axially relative to the part

  outside for the adjustment of the functional clearances.

  When a separate guide element is provided, it is judiciously supported on the closure element, radially

  movable relative to the longitudinal axis of the outer part.

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  In addition, it is advantageous that the inner part between the outer spherical surface and the guide surface is provided with a free surface which is set back with respect to these two surfaces towards the central point of the joint. Thanks to this, we can positively influence the

  friction ratios by reducing friction surfaces.

  This also applies when the outer spherical surface of the inner part ends before a transverse plane which contains the point

joint center.

  By embodying the invention, the outer spherical surface of the inner part, which is used to guide the cage, corresponds in diameter to the spherical guide surface, and the centers of the guide surface and the outer spherical surface are centered. on the central point of the joint. The guide surface can be produced in the form of a hollow spherical cap surface, in case a separate guide element is provided. Such an implementation principle is described, for example, in document DE 42 08 786 or in German patent application P 43 17 606.2. Here, it is advisable that the guide surface has grooves which also extend in meridian planes relative to the longitudinal axis of the inner part. Thanks to this, the surfaces to

  stamping are reduced and the processing force required decreases.

  In addition, the grooves in which grease is stored can be used as lubricant reserve chambers, which can be used to lubricate the surfaces of the interior part and the

  guides that slide one over the other.

  Preferably, the grooves are arranged in the guide surface between

  two adjacent interior rolling grooves.

  Two preferred embodiments of the invention are illustrated

schematically in the drawing.

  The figures show: fig. 1 a longitudinal section along the section line I - I of FIG. 2 through a first embodiment of a constant velocity joint according to the invention, the outer part and the inner part being aligned; fig. 2 a partial cross section of FIG. 1 along the section line II - II of FIG. 1, and fig. 3 a second embodiment of a joint according to the invention in longitudinal section, the inner part being inclined relative to the outer part, and there is provided a cutting path which corresponds to that

of fig. 1.

  Figs. 1 and 2 show a first embodiment of a joint

  homokinetic spherical turn produced in the form of a fixed joint.

  The constant velocity joint consists of an external part 1 which is produced in the form of a sheet metal part and in a hollow manner. The inner space of the outer part I is designated by the reference 5. The resulting inner surface in the inner space 5 is designated by the reference numeral 2. In the inner surface 2 of the outer part 1, arrangements have been made external rolling grooves 3 extending in meridian planes relative to the longitudinal axis 4 of the external part. In addition, the outer part 1 is provided with a closure element 7 which comprises connecting members 6, for example in the form of a stud or the like, which serves to connect the outer part 1 with an element which drives or is to be rotated. The closing element 7 is produced in such a way that a rotationally secured connection is obtained with the external part 1. For fixing the closing element 7 relative to the external part 1, a connection is used for example. welded 8 in the form of an electron beam weld or several weld points distributed over the periphery. A rotational connection is obtained by engaging protrusions of the closure element 7 in several grooves of

outer bearing 3.

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  An inner part 9 is arranged in the inner space 5 of the outer part 1. The inner part 9 has an outer surface 10 formed by several sections. On the outer surface 10, there have been formed in meridian planes with respect to the longitudinal axis 16 of the inner part of the inner rolling grooves 13 distributed at the periphery, which are respectively opposite a groove outer bearing 3 of the outer part 1. The inner bearing grooves 13 and the outer bearing grooves 3 are produced without undercut from the side 11 of the seal. The closing element 7 is fixed in the direction of the side 11. As for the side 11, it is therefore the closed side of the seal, while the side 12 situated opposite it represents the open side of the joint, from which the

  inner part 9 is accessible for the establishment of a tree.

  The internal rolling grooves 13 are arranged only on a small section of the axial length of the internal part 9. Groove sections 14, 15 widened respectively in cross section relative to the internal rolling grooves 13, are connected towards the two sides 11, 12 to the inner rolling grooves 13. The inner rolling grooves 13 are produced, starting from the side 11, without undercut. They have a length 17 relative to the longitudinal axis 16 of the inner part, which consists of a "ball stroke" 18 or active stroke and safety lengths 19 at the respective ends. The inner rolling grooves 13 have grooves 32 which extend over their length and which are arranged in their bottom. The ball stroke 18 will be described in more detail below. The central point of the joint around which the inner part 9 can be bent relative to the outer part 1, is designated by the reference 20. The outer surface 10 of the inner part 9 has, in the direction of the side 12, an outer spherical surface 21 of which the center is centered on the central point 20 of the joint. In the direction of the side 11, there is a guide surface 23 which is also produced in the form of a spherical cap surface and the center of which is also centered on the central point 20 of the joint. The outer spherical surface 21 ends before a transverse plane 28

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  which cuts at right angles the longitudinal axis 16 of the interior part passing through the central point 20 of the joint, seen from the side 12 on the

transverse plane 28.

  Between this end and the guide surface 23, a free surface 22 is provided which is set back with respect to the outer spherical surface 21 and to the guide surface 23. Preferably, the outer spherical surface 21 and the guide surface 23 have the same diameters. The free surface 22 leaves an interval relative to an imaginary extension of an enveloping whose diameter corresponds to the spherical diameter of the outer spherical surface 21 or of the surface of

guide 23.

  In the interval between the inner surface 2 of the outer part 1 and the outer surface 10 of the inner part 9, a cage 24 is arranged which has a hollow spherical cap surface 25 with which it is guided on the outer spherical surface 21. In addition, the cage 24 has a substantially spherical outer surface 26 which is arranged at a distance from the inner surface 2 of the outer part 1. The cage 24 has, in correspondence with the distribution of the outer rolling grooves 3 and internal rolling grooves 13, windows 27 distributed around the periphery. The external rolling grooves 3 and the internal rolling grooves 13 located opposite each receive a ball 31. Each ball 31 is

  guided in a window 27 of the cage 24.

  Starting from the extended position of the outer part 1 and the inner part 9, in which the longitudinal axis 4 of the outer part is in exact alignment with the longitudinal axis 16 of the inner part, when tilting of the joint for which for example the inner part 9 is inclined relative to the outer part 1 around the central point 20 of the joint in a clockwise direction in the plane of the drawing according to FIG. 1, it results in a change in position

9 2717769

  of the ball 31, so that the ball 31 moves jointly with the cage 24 to the right in the position illustrated in phantom lines to the right next to the balls 31 illustrated in solid lines. The point of contact between the inner rolling groove 13 and the ball 31 occurs at a point of intersection formed by a plane which extends at right angles to the longitudinal axis 16 of the inner part through the point central of the ball 31 and through the central point 20 of the joint, and through the inner rolling groove 13. Thanks to this is formed one of the ends of the ball stroke 18 as end position 30. From 'a position according to fig. 1, during the tilting of the inner part 9 with respect to the outer part 1 in an anti-clockwise direction around the central point 20 of the joint, an extreme position 29 occurs. The distance between the two extreme positions 29, 30, projected onto the longitudinal axis of the inner part, represents the ball stroke 18. The length 17 of the inner rolling grooves 13 is however extended at the ends respectively of a safety length 19 also related to the axis longitudinal 16 of the inner part. The safety lengths 19 result mainly from the fact that the balls must be guided and securely retained also in the extreme positions 29, 30. This applies taking into account the

tolerances that occur.

  In the closure element 7, there is a recess 33 which has a bearing surface 34 extending radially relative to the longitudinal axis 4 of the outer part. A guide element 36 is guided in a radially movable manner in the recess 33. This guide element 36 bears with a plane surface in a movable manner against the bearing surface 34. Between the outer peripheral surface of the element guide 36 and the wall delimiting the recess 33, an elastic ring 37 is arranged which retains the guide element 36, but which allows its radial displacement. In addition, the guide element 36 has on its side diverted from the bearing surface 34 a guide surface 35 which is produced in the form of a hollow spherical cap surface, and which bears axially against the surface. guide 23 of the inner part 9. During assembly of the seal, the preassembled unit, consisting of the inner part 9, the cage 24 and the balls 31 is introduced into the outer part 1. Next, the closure element 7 together with the guide element 36 retained thereon by the elastic ring 37 in the outer part 1, and the whole unit is moved to the left in FIG. 1 as far as the necessary functional clearances are formed, after which the closure element 7 is fixed relative to the external part 1 by means of

welding 8.

  The inner part 9 also has a bore 38 which is centered on the longitudinal axis 16 of the inner part. Rolling grooves 43 are arranged in peripheral distribution in the bore 38. The rolling grooves 43 of a shaft 42 inserted in the bore 38 are located opposite these rolling grooves 39. The rolling grooves 39 , 43 each receive balls 40 arranged in distribution in pairs along the longitudinal axis 16 of the inner part and retained by a cage 41, so that a movement to the left

  between the inner part 9 and the shaft 42 is possible.

  The inner part 9 is produced in one or more forming operations without removing material. Thanks to the groove sections 14, widened in cross section and connecting to the rolling grooves 13, and thanks to the grooves 32 in the bottom of the rolling grooves 13, this results in reduced contact surfaces, which require a reduced need for energy during forming without removing material. In addition, it results in improved dimensional stability, because due to the lower forces and the possibility of the material escaping during forming, the tools which receive the inner part 9 are less stressed. A faster creep of the material is established. Internal parts 9 of the type described are preferably produced from steel

hardenable by case hardening.

  In the second embodiment of a seal according to the invention, there is an outer part 1 made in the form of a shaped sheet metal part, with which is associated a closure element 7 which undergoes 11 a connection. with the outer part I by deformed sections 8. The inner part 9 has as a guide surface 23 for a guide element 36, a hollow spherical cap surface whose

  center is centered on the central point 20 of the joint.

  In the guide surface 23 produced in the form of a hollow spherical cap surface, grooves 44 are arranged, distributed in meridian planes with respect to the longitudinal axis 16 of the inner part, which are offset at the periphery. relative to the inner rolling grooves 13 respectively by half the distance of the inner rolling grooves 13. Thanks to these grooves 44, the surface area of the guide surface 23 is reduced. In addition, free spaces are produced for the creep of the material during stamping, so that the surface 23 produced in the form of a hollow spherical cap surface can be produced without removal of material together with the grooves of inner bearing 13. The inner bearing grooves 13 extend directly from the side II 1, so that there are only side sections 15 on the side 12 which have an enlarged cross section with respect to

  to the inner rolling grooves 13.

  The closure element 7 has a recess in the direction of the guide element 36 received by the guide surface 23; this recess has the bearing surface 34 on which the guide element 36 is arranged with a corresponding bearing surface, movable radially relative to the longitudinal axis 4 of the outer part. As regards the shortened rolling grooves, the invention can also be used on external parts which are

massive pieces.

  List of references 1 external part 2 internal surface 3 external rolling grooves 4 longitudinal axis of the external part internal space 6 connecting member 7 closing element 8 connection 9 internal part external surface of the internal part 11, 12 sides 13 rolling grooves internal 14, 15 cut-off section 16 longitudinal axis of the internal part 1 7 length 18 stroke of the balls 19 safety length 20 central point of the joint 21 external spherical surface 22 free surface 23 guide surface 24 cage 25 hollow spherical cap surface 26 external surface of the cage 27 window 28 transverse plane 29, 30 extreme positions 31 ball 32 groove 33 recess 34 bearing surface bearing surface 36 guide element 37 elastic ring 38 drilling 39 rolling groove ball 41 cage 42 shaft 43 rolling groove 44 throat

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Claims (13)

Claims   1. CV joint comprising a hollow external part (1), in the internal surface (2) of which external rolling grooves (3) are formed in meridian planes relative to the longitudinal axis (4) of the external part , and comprising an internal part (9) arranged in the internal space (5) of the external part (1), in the external surface (10) of which are formed internal rolling grooves (13) in meridian planes relative to its longitudinal axis (16) of the inner part, these inner rolling grooves being located opposite the outer rolling grooves (3), the inner rolling grooves (13) and the outer rolling grooves ( 3) located respectively opposite opposite jointly a ball (31) for the transmission of the torque, these balls being guided in windows (27) of a cage (24) arranged in the interval between the inner face (2) of the outer part (1) and the outer surface (10) of the inner part (9), and the inner rolling grooves (13) and the outer rolling grooves (3) being produced, starting on one side (11) of the joint, without undercut, and the cage (24) being guided with a hollow spherical cap surface (25) on an outer spherical surface (21) of the inner part (9), characterized in that the rolling grooves (13, 3) of the inner part (9) and / or the outer part are restricted to a length (17) which consists of the stroke (18) of the balls (31) in the rolling grooves (13), which results from the maximum inclination planned by the construction between the internal part (9) and the external part (1) during rotation, and of a safety length (19) to both ends, and in that the rolling grooves (13) are transformed at least at one end respectively in a groove section (14, 15) which has an enlarged cross-section relative to the rolling grooves (13), and in that the inner part (9) or the outer part (1) which has the shortened rolling grooves is made by forming without removing material, and at least the rolling grooves are stamped to the final dimension.   2. CV joint according to claim 1, characterized in that the internal rolling grooves (13) are   provided with at least one groove (32) which extends over their length (17).   3. constant velocity joint according to claim 1, characterized in that the safety length (19) is dimensioned so that taking into account the tolerances which occur, the balls   are also guided in the extreme positions.   4. constant velocity joint according to any one of claims 1 to 3,   characterized by the embodiment in the form of a fixed constant velocity joint, in which the outer part (1) having the outer rolling grooves (3) is closed by a closing element (7) on the side (11) from which begins the absence of an undercut, and in which the inner part (9) is provided, in the direction of the closure element (7), with a guide surface (23) which is produced in the form of a spherical surface, and in addition, the outer spherical surface (21) is arranged on the side of the inner part (9) which is diverted from the guide surface (23).   5. CV joint according to claim 4, characterized in that the inner part (9) and the outer part (1) are centered with respect to each other on the one hand thanks to the support of the surface of guide (23) of the inner part (9) against a bearing surface (35) of the closure element (7) or against a guide element (36) supported thereon in the direction of the longitudinal axis (4) of the external part, and on the other hand thanks to the support of the balls (31) in the external rolling grooves (3) and in the cage (24), a clearance being provided between the external surface (26 ) of the cage (24) and the surface   inside (2) of the outside part (1).   6. constant velocity joint according to claim 4, characterized in that the inner part (9) and the outer part (1) are centered relative to each other on the one hand thanks to the support of the surface of guide (23) against the bearing surface (35) of the closure element (7) or against a guide element (36) pressed against it in the direction of the longitudinal axis (4) of the external part , and on the other hand thanks to the guide of the cage (24) comprising a spherical outer surface on a hollow spherical surface of the part exterior (1).   7. CV joint according to any one of claims 4 to 6,   characterized in that the closing element (7) can be moved relative to the external part (1) in the direction of the longitudinal axis (4) of   the external part for the adjustment of the functional clearances.   8. constant velocity joint according to either of claims 5 and 6,   characterized in that the guide element (36) is supported radially mobile relative to the longitudinal axis (4) of the part   outside against the closing element (7).   9. constant velocity joint according to any one of claims 4 to 8,   characterized in that the inner part (9) is provided, between the outer spherical surface (21) and the guide surface (23), with a free surface (22) which is set back from these two surfaces towards the point central (20) of the seal.   10. CV joint according to any one of claims 4 to 9,   characterized in that the outer spherical surface (21) of the inner part (9) ends before a plane which contains the central point (20) of the joint.   I 1. CV joint according to any one of claims 4 to 6,   characterized in that the outer spherical surface (21) of the inner part (9), which is used for guiding the cage (24), corresponds in diameter to the spherical guide surface (23), and in that the centers the guide surface (23) and the outer spherical surface (21)   are centered on the central point (20) of the joint.   12. CV joint according to any one of claims 4 to 6,   characterized in that the guide surface (23) of the inner part (9)   is made in the form of a hollow spherical cap surface.   13. CV joint according to claim 12, characterized in that the guide surface (23) produced in the form of a hollow spherical cap surface has grooves (44) extending in meridian planes relative to the longitudinal axis (16) of the inner part.   14. CV joint according to claim 13, characterized in that the grooves (44) are arranged in the guide surface (23) respectively between two inner rolling grooves (13) neighbors.